Erratum: Heats of Combustion of Some Peroxides and the Heats of Formation of Acetate, Propionate, and Butyrate Radicals

1958 ◽  
Vol 28 (2) ◽  
pp. 355-355
Author(s):  
I. Jaffe ◽  
E. J. Prosen ◽  
M. Szwarc
1956 ◽  
Vol 34 (5) ◽  
pp. 626-648 ◽  
Author(s):  
Keith J. Laidler

An analysis has been made of the heats of formation and combustion of organic gases and liquids, and of the heats of vaporization of liquids. The work has been done as far as possible with homologous series, in order to discover systematic effects. The data are converted into heats of atomization, i.e., the heats required to convert the gases or liquids into their constituent atoms. It is shown that the heats of atomization of the gaseous aliphatic hydrocarbons (paraffins, olefins, and acetylenes) can be accurately represented by a scheme in which a distinction is made between primary, secondary, and tertiary carbon–hydrogen bonds, and between bonds that are next to, and next but one to, multiple bonds. For aromatic molecules an appropriate correction for resonance is proposed. For other types of compound it is found that suitable values for the various bonds (e.g., C–CHO, C–OH) will give rise to good agreement with experiment.It is shown that to a reliable approximation heats of vaporization are also amenable to the same treatment. Since this is so it is possible to assign bond values on the basis of which it is possible to make predictions about heats of formation of liquids.A system of coefficients is worked out by means of which the numbers of atoms of various kinds in a molecule can be expressed in terms of the numbers of the different kinds of bonds. On the basis of these it is shown how bond contributions to heats of formation and heats of combustion can be calculated. A table (Table X) gives the contributions proposed for the heats of atomization, heats of formation, and heats of combustion for both gases and liquids.


A method has been evolved for measuring the heats of combustion of spontaneously inflammable substances in the bomb calorimeter and applied to the following compounds: zinc dimethyl, zinc diethyl, zinc di- n -propyl, zinc di- n -butyl, cadmium dimethyl, boron trimethyl and aluminium trimethyl. The samples used were subjected to very thorough purification, revised melting points being given for cadmium dimethyl and aluminium trimethyl. The heats of formation, deduced by the application of additional thermal data, have been listed with all those so far determined for the metal alkyls, and the energies of dissociation and bond energies of the metal-carbon links estimated. This has entailed a recalculation of the heats of sublimation of aluminium and tin. From a comparison of the values obtained for the dissociation energies with evidence from spectroscopic and kinetic studies, a definite necessity for taking into account the energies required to promote the various elements to the states of maximum valency is apparent.


1975 ◽  
Vol 30 (3) ◽  
pp. 347-355 ◽  
Author(s):  
P. Potzinger ◽  
A. Ritter ◽  
J. Krause

The appearance potentials for a large number of organosilicon ions have been measured. Combination of these values with thermochemical heats of combustion allow the determination of bond energy terms which may be used to calculate heats of formation for all silicon compounds containing hydrogen, alkyl and chlorine ligands. The bond dissoziation energies D(Si - H)= 89 ± 4, D(Si - C) = 85 ± 4 and D (Si - Si) =75 ± 8 kcal/Mol were found to be independent of the number of methylgroups attached to silicon. In addition the Si - Cl bond energy was found to be 116 and 104 kcal/Mol in (CH3)3SiCl and Cl3SiCl respectively.


The study of the explosive properties of organic nitrobodies is not complete without a knowledge of their heats of formation, for these constants are closely related to their stability and sensitiveness to impact and heat. The heats of formation also form the basis of any calculations of the energy liberated in the detonation of high explosives. The heats of detonation of balanced explosives such as a mixture of ammonium nitrate and trinitrotoluene arranged for complete combustion, can readily be determined from the heats of formation. When there is insufficient oxygen in the explosive for the complete combustion of the hydrogen and carbon it is more difficult to calculate the heat of detonation, especially as the composition of the products is dependent on the external work done by the gases, but from a knowledge of the constants of gaseous and heterogeneous equilibria it is often possible to obtain values with some degree of accuracy. The preliminary work in the production of new explosives can often be considerably shortened by such calculations. The heats of combustion of some of the members of the toluene, benzene and phenol series have been determined by various workers, but there are many gaps in the series, and the agreement in certain cases is unsatisfactory. These results are summarised in Table I.


1962 ◽  
Vol 35 (3) ◽  
pp. 661-664
Author(s):  
W. D. Good ◽  
J. L. Lacina ◽  
J. P. McCullough

Abstract The heats of combustion and formation were determined for tetramethylthiuram monosulfide [bis-(dimethylthiocarbamoyl) sulfide] and tetramethylthiuram disulfide [bis-(dimethylthiocarbamoyl) disulfide]. The S—S thermochemical bond energy in tetramethylthiuram disulfide was shown to be about the same as in normal alkane disulfides and in S8. Rotating-bomb combustion calorimetry was found satisfactory for compounds that contain both sulfur and nitrogen.


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